Free-fall plunger



Jan. 18, 1966 H. H. LUNEBRING 3,229,768

FREE-FALL PLUNGER Filed Deo. 20, 1962 2 Sheets-Sheet l pm i i L Si L1 f\ W ,Mm MJ fig Jan. 18, 1966 H. H. I UNEBRING 3,229,768

FREE-FALL PLUNGER Filed Dec. 20, 1962 2 Sheets-Shea?l 2 @Will United States Patent O 3,229,768 FREE-FALL PLUNGER Herman H. Lunebring, Shreveport, La., assignor to Macco Oil Tool Co., Inc., a corporation of Texas Filed Dec. 20, 1962, Ser. No. 246,226 5 Claims. (Cl. 166-17 0) This invention relates to new and useful improvements in plungers for use in wells, and particularly plungers for lifting gas and oil in well pipe and for scraping paratin from such pipe.

An object of this invention is to provide a new and improved plunger for use in wells which is adapted to be raised in a well pipe by well pressure to effect a lifting of fluid thereabove and which is also adapted to fall freely by gravity after reaching its upper limit of travel for such lifting.

An important object of this invention is to provide a new and improved free-fall plunger having outwardly expansible means adapted to engage the inside of a pipe as the plunger is moved upwardly therein and which is also adapted to be retracted for providing an external by-pass of uid as said plunger falls by gravity in the pipe.

Another object of this invention is to provide a new and improved plunger which has an annularly expansible means which is adapted to be retracted and locked in the retracted position for permitting the plunger to fall by gravity in a pipe.

A further object of this invention is to provide a new and improved plunger for use in a well pipe wherein wiper means are adapted to be resiliently held in an expanded position in contact with the inside of the pipe until the plunger reaches an upper point, and wherein means are provided for retracting said wiper means to -by-pass fluid externally thereof so that the plunger may freely fall through uid in the well pipe.

Still another Vobject of this invention is to provide a new and improved plunger for use in well pipe, wherein wiper means are adapted to be resiliently held in an expanded position in contact with the inside of the pipe until the plunger reaches an upper point where it is retracted, and wherein the wiper means is adapted to be released from the retracted position and re-expanded upon reaching a lower limit in the pipe for an automatic repetition of the upward lifting movement of the plunger in the pipe and its return t-o the lower limit.

A further object of the present invention is to provide a plunger for use in well pipe with retractable members which may be withdrawn from contact with the inner surface of the well pipe to provide an annular opening about said plunger within the well pipe to allow the plunger to freely fall to the bottom of the well pipe.

Still a further ob-ject of the present invention is to provide a new and improved plunger with lateral members which will be automatically expanded to engage the wall of the well pipe when the plunger reaches the bottom of the well pipe.

Another object of the present invention is to provide a new and improved free fall plunger having a plurality of wiper elements adapted to wipe or scrape the inner surface of the well pipe throughout its entire circumference at each elevation.

Another important object of the present invention is to provide a free fall plunger with members which can be laterally expanded under adjustable tension to positively engage the side wall surface of well pipe to clean or wipe paraffin or other foreign matter therefrom.

A particular object `of this invention is to provide in combination with a free-fall plunger having an expansible pipe wiper means engageable with the inside of a pipe, an actuating assembly at the upper limit of travel of said 3,229,768 Patented Jan. 18, 1966 ICC plunger for cooperating with the plunger to effect a retraction `of said wiper means for enabling iluid to by-pass around said plunger as it falls through the fluid in the pipe.

The preferred embodiment of this invention will be described hereinafter, together with other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIG. l is an elevation, partly in section, illustrating the apparatus of this invention with the plunger thereof rising in a well pipe;

FIG. 2 is a vertical sectional view illustrating details of the plunger and the actuating assembly fof the apparatus of this invention, with the plunger in the expanded position corresponding to that illustrated in FIG. l';

FIG. 3 is a view similar to FIG. 2, but illustrating an intermediate position of the plunger at the upper limit of its travel, wherein such plunger is being actuated through a cooperation with the actuating assembly to effect a return yof the plunger to a retracted position;

FIG. 4 is a vertical sectional view similar to FIG. 3, but illustrating the plunger in the retracted position at the upper end of the well pipe or tubing; and

FIG. 5 is a sectional view taken on line 5-5 of FIG. 3.

In the drawings, the letter P designates general-ly the plunger or wiper apparatus of this invention which is adapted to be used in a well pipe or tubing T. The tubing T is of conventional construction and ordinarily includes a tubing collar C with a collar recess C formed therewith in the known manner. The tubing string T normally extends into a conventional well casing W, with the upper end of the tubing T having a discharge pipe or outlet T in conjunction with a Christmas tree or similar surface equipment. In use, the plunger P is adapted to be forced upwardly in the tubing string T by uid pressure from a well formation therebelow until the plunger P contacts an upper stop means or `actuating assembly A which serves to move the plunger P to a retracted position, as will be more fully explained hereinafter, 4so that the plunger P may then drop in the iluid by gravity. During the fall of the plunger P, the fluid such as oil and/or gas in the well by-passes externally of the plunger P so that a large maximum by-pass area is thus provided to avoid inhibiting the dropping of the plunger P as much as possible. The lower limit of travel of the plunger P is determined by a suitable stop means S of known construction which is preferably a stop collar mounted in the collar recess C. When the plunger P contacts the upper surface of the stop means S, it is automatically returned to the expanded position, as will be more fully explained, so that the fluid therebelow again exerts pressure on the plunger P to move it upwardly in the tubing or pipe T. The upward movement of the plunger Pfand its subsequent return are repeated automatically as the-plunger P moves from its lower limit at the stop means S to its upper limit at the actuating assembly A, as will be more fully explained. With the apparatus of this invention, uid above the plunger P when the plunger P has reached its lowermost position is thus lifted upwardly and discharged through the outlet T for each upward stroke of the plunger P. Also, the internal surface of the tubing T is scraped to remove paraffin or other foreign deposits during each upward stroke of the plunger P.

Considering the invention more in detail, and particularly the plunger or wiper apparatus P, such apparatus P includes an inner mandrel or rod which preferably has external threads 10a at the upper ends for receiving a nut 11 having corresponding internal threads 11a. An expander sleeve 14 is adapted to be positioned on the mandrel 10 for limited longitudinal movement with.

respect thereto. Such expander sleeve 14 has an internal recess 14a at its upper end for telescopically receiving the nut 11 as best seen in FIG. 2. The final position of,` the nut 11 on the mandrel 10 is maintained, preferably by a pin 15 which extends through the walls of the nut 11 and a notch 10b at the upper end of the mandrel 10. It is to be noted that the upper end 11b of the nut 11 is preferably closed for a purpose to be hereinafter described. The lower annular edge 11C of the nut 11 is adapted to contact an internal shoulder or lateral surface 14b to limit the upward movement of the expander sleeve 14 with respect to the mandrel 10.

The upper end of the expander sleeve 14 preferably has an annular downwardly and outwardly -inclined surface 14C, and below such surface 14C, a shing neck 14d of conventional construction is provided to enable the plunger P to be fished from the pipe T if it should become necessary.

The expander sleeve -14 also has longitudinally spaced upwardly and outwardly inclined expander surfaces 14e and 14)c which are formed with an annular recess '14g therebetween. Principally for assembly purposes, the expander sleeve 14 is provided with a lower internal counterbore 14h which is adapted to receive a Isleeve extension 17 which actually forms a part of Iand an extension of the sleeve 14 in operation. The sleeve 17 has a smaller external diameter 17a as compared to the external diameter 14k at the lower end of the sleeve 14 so as to provide a longitudinal slot 18 between a lower shoulder 14p on the sleeve 14 .and a tapered guide surface 17b on the sleeve extension 17. The sleeve 17 also has a lower annular surface 17C and an internal bore 17d which preferably is of the same internal diameter as the bore 14t of the sleeve 14 so that both the sleeve 14 and the sleeve extension 17 are adapte-d to move together longitudinally with respect to the mandrel 10.

The plunger P has a tubular body 20 at or near its lower end which is formed with a main bore 20a, an intermediate bore 20b, and an inner Ibore 20c, with an annular laterally extending shoulder 20d formed between the intermediate bore 20h and the inner bore 20c. Also, because the main bore 20a is of a greater diameter than the intermediate bore 20h, an annular shoulder 20e is formed therebetween, Ibut such shoulder 20e may be omitted if desired, as will be more evident hereinafter.

The body 20 surrounds the mandrel 10 near its lower end so as to position the shoulder 20d above a laterally extending shoulder 10c on the mandrel 10 therebelow in order to receive a coil spring 22 or a similar resilient member therebetween. The mandrel 10 also has another shoulder 10d disposed inwardly and above the shoulder 10c, and below the lower end 17C of the extension 17 so as to receive a spring 25.

For providing a wiping contact with the internal surface of the well pipe or tubing T throughout the full circumference at each elevation as the plunger P moves upwardly in the pipe or tubing T, an expansible means is provided which includes a plurality of wiper members 30. Each of the wiper members 30 is preferably an arcuate segment of a cylinder so that the plurality of members 30 form a cylinder engageable with the inside surface of the pipe or tubing T. Although such members 30 may be formed of various materials, they are preferably formed of a material such as polytetrauoroethylene sold under the trademark Teflon Each of the wiper members 30 is secured to the body 20 by a pivotal connecting link 25 which preferably extends within a longitudinal slot 30a of each member 30. The upper end of each link 2S may have la pin opening l25a which is elongated 'as Icompared to a pivot pin 31 extending therethrough. The lower end of each link 25 is pivotally connected to the upper end of the body 20 by a pivot pin 32 which is adapted to be positioned in a recess 20f of the body 20. Also, the body 20 is provided with longitudinal slots 20g for permitting lateral pivotal movement of the link-s 25 as the members 30 move inwardly and outwardly with respect to the sleeve 14.

In order to guide the movement of the members 30 outwardly from the retracted position (FIG. 4) to the expanded position (FIG. 2), each of the members 30 is provided with longitudinally spaced upwardly and outwardly inclined. surfaces 30b and 30C which are adapted to engage the surfaces 14e and 14f, respectively, of the expander lsleeve 14. Thus, as the expander sleeve 14 moves downwardly relative to the wiper members 30, the inclined surfaces 14e and 14f cause an outward movement of the members 30 by causing a pivoting of each lof the members 30 outwardly about the links 25 with the surfaces 14e and 14]c in engagement with the surfaces Sb and 30e, respectively. Because of the longitudinally spaced coacting surfaces 14e and 14f which are in engagement with the surfaces 30h and 30e, respectively, the external surface 30d of each member 30 remains parallel, or substantially parallel to the inside surface of the tubing or pipe T. Such parallel alignment of the external surface 30d of each member 30 with the inside surface of the pipe T assures a uniform` and large surface area contact between such internal surface of the pipe T and the external surface 30d of each of the members 30 for effective wiping action to remove paran from the inside of the pipe T and also to assure an adequate seal for the lifting of the fluid above the members 30 as the plunger P moves upwardly in the pipe T.

Since the members 30 move inwardly and outwardly, and are separate from each other for such pivotal movement, an interlocking seal means is provided which in the preferred form includes interlocking projections 30e (FIG. 1) which intert in corresponding recesses 301". It will be understood that such interlocking seal between adjacent longitudinal edges of the members 30 is provided between each of the adjacent members 30 so that there is a complete circumferential seal at all times with the internal surface of the pipe T when the members 30 are in the expanded position. However, the projections 30e are of a length equal to the depth of the recesses 301, or shorter than such depth, so that the members 30 can completely collapse and engage the longitudinal edges thereof in the retracted position (FIG. 4). The particular length of the projection 30e and the depth of the recesses 30] are thus normally determined by the extent to which the members 30 must expand for the particular internal diameter of the pipe T in which the plunger P is used, and therefore such dimensions will vary depending upon the. particular diameter of the pipe T in Which the device P is used.

As will be more evident hereinafter, the spring or resilient means 22 acts to urge the mandrel 10 and the expander sleeve 14 downwardly relative to the wiper ele-- ments 30 so as to resilient urge the members 30 into en gagement With the inside surface of the pipe T. When. the device is actuated outside of a pipe, the maximum: expansion of the members 30 is limited by the engagement of a hook 25b on each of the pivot links 25 with the shoulder 14p (FIG. 2). Also, each of the links 25 has a tapered inner surface 25C which is adapted to engage the taper 17h to assist in maintaining the members 30 in a substantially parallel position to the mandrel 10 in the retracted position (FIG. 4).

In order to lock the plunger P in the retracted position of FIG. 4 during the falling of the plunger P in the pipe T, the lower end of the mandrel 10 is formed with one or more locking pins 40, two of which are shown, and which are adapted to slide laterally within lateral openings e. Such pins 40 extend into a central recess or opening 10Jc in the lower end of the mandrel 10 for engagement by a longitudinally movable locking head 41 having a substantially cylindrical upper portion 41a and downwardly and inwardly inclined or tapered lower portion 41b therebelow.

The pins 40 are adapted to enter an annular groove 20h when the mandrel 10 has moved upwardly relative to the body 20 to laterally align the locking pins 40 with such groove 20h. Although it is preferred to employ a circumferential groove 20h for receiving the pin or pins 40, a separate recess or opening for each pin 40 of substantially the same diameter as the pin 40 may be provided instead of the complete circumferential groove 20h, but in such instance, it would require a more accurate positioning of the pin 40 wtih the opening to be aligned therewith. By the use of the complete circumferential groove 20h, the pin or pins 40 are in a position to enter such groove when aligned in the same circumferential plane regardless of the particular rotational position of such pin or pins 40 with respect to the groove 20h.

When the pin or pins 40 are circumferentially aligned with the recess Ior groove 20h, the locking head 41 is urged downwardly so that the tapered surface 41b forces the looking pin or pins 40 outwardly into the groove 20h by a resilient spring 45. After the tapered portion 41b has moved the pins 40 outwardly, the substantially cylindrical upper portion 41a of the locking head 41 moves into position in contact with and inwardly of the inner surfaces of the pin or pins 40 to thereby lock such pins 40 in an extended position as best seen in FIG. 4.

The lower extent of travel of the head 41 is controlled by means of a ilange 41C connected below the locking head 41, and which is adapted to engage the inside surface 46a of a threaded bushing 46 in the lower end of the mandrel 10.

A release rod S0 which is preferably integral with the locking head 41 extends downwardly from the flange 41C and through the bushing 46, projecting below the lower end of the mandrel 10. When the release rod 50 is urged upwardly by contact with the upper surface 51 of a stop collar or element S (FIG. 1), the cylindrical portion 41a is moved upwardly above the locking pins 40 so as to permit the pins 40 to move inwardly. The pins 40 are actually urged inwardly by the downward pressure exerted by the resilient spring 22 so as to eifect a release of the pins 40 from `the recess 20h, and to allow such pins 40 to drop or move below such recess 20h to the released position shown in FIG. 2, at which time the elements 30 are also expanded to their expanded position shown in FIG. 2. Preferably, the lower surface of the groove 20h is inclined downwardly and inwardly to provide a guide for the pins 40 to move inwardly as the spring 22 urges the mandrel 10 downwardly to release the pins 40 from the groove 20h.

As the plunger P rises in the pipe T it engages the actuating assembly A Which is positioned `at the top of the pipe T above the discharge pipe or outlet T for actuating the release mechanism of the plunger P to retract the retractable members 30 from engagement with the pipe T and allow the plunger P to fall in the pipe, as will be evident hereinafter. The actuating assembly A is preferably secured to the end of the tubing T by a cap K which is attached by threads or other suitable means to the upper end of the tubing or pipe T.

The actuating assembly A includes an actuator body or base 60 which ts slidably within an actuator sleeve 62; both the actuator base 60 and the actuator sleeve 62 are preferably of cylindrical configuration.

The actuator base 60 has an upper surface 60a which engages the cap K or other suitable stop t-o prevent any upward travel of the actuating assembly A when it is engaged by the plunger P.

To prevent the actuating assembly A from falling in the tubing T, the actuator sleeve 62 is preferably formed with an external annular shoulder 62a which engages the upper end E of the tubing T. The surface 62a and the end E may be inclined inwardly and downwardly to facilitate the positioning of the actuating assembly A centrally in the tubing T.

In order to lock the actuator sleeve 62 against movement upwarly in relation to the actuator base 60, the actuator base is formed with one `or more locking pins 61, two of which are shown, and which are adapted to slide laterally within lateral openings 60b. Such pins 61 extend into a central recess or opening 60C in the actuator base 60 for engagement by a longitudinally movable locking head 63 which is preferably substantially cylindrical and which has smaller diameter portion 63a therebelow and preferably a downwardly and inwardly inclined or tapered lower portion 63b.

The pins 61 are adapted to enter an annular groove 62h when the actuator sleeve 62 has moved downwardly relative to the actuator body or base 60 to laterally align the locking pins 61 with such groove 62h. Although it is preferred to employ a circumferential groove 62h for receiving the pin or pins 61, a separate recess or opening for each pin 61 of substantially the same diameter as the pin 61 may be provided instead of the complete circumferential groove 6217, but in such instance, it would require a more accurate positioning of the pin 61 with the opening to be aligned therewith. By the use of the complete circumferential groove 62b, the pin or pins 61 are in a position to enter such groove when aligned in the same circumferential plane, regardless of the particular rotational position of such pin or pins 61 with respect to the groove 62h.

When the pin or pins 61 are circumferentially aligned with the recess or groove 6211, the locking head 63 is urged downwardly by a resilient spring 63d so that the tapered surface 63b forces the locking pin Ior pins 61 outwardly into the groove 62b. After the tapered portion 63b has moved the pins 61 outwardly, the locking head 63 moves into position in contact -with and inwardly of the inner surfaces of the pin or pins 61 to thereby lock such pins 61 in an extended position asbest seen in FIG. 2.

A release rod 63C, which is preferably integral with the locking head 63 extends into an opening 64a in a release piston 64.

The release piston 64 which ts slidably within the actuator sleeve 62 has an annular surface 64e at its lower end which is preferably tapered down-wardly and inwardly. The actuator sleeve 62 has an internal annular surface 62e which is also preferably tapered downwardly and inwardly to serve as a stop for limiting the downward movement of the release piston 64.

A resilient spring means 65 is positioned around the release rod 63 within the bore of the actuator sleeve 62 and is provided to urge the release piston 64 downwardly in relation to the actuator base 60.

The actuator sleeve 62 has a lower internal annular surface 62d which is formed below the internal annular surface 62e. In the preferred embodiment, the surface 62d is tapered outwardly and downwardly at the lower end of the actuator sleeve 62 to receive the correspondingly tapered portion 14o of the expander sleeve 14 of the plunger P. The release piston 64 is formed with a lower surface 64d which is provided to receive the upper end 11b of the nut 11 of the plunger P.

As shown in FIG. 'l of the drawings, the preferred form `of the stop means S has an upper surface 51 which is preferably solid for contact by the release pin 50 of the plunger P. The stop S may be of a conventional construction and, as shown, has radially or laterally expansible legs 51a with projections Sllb at the lower end thereof which lit into the collar recess C. In lowering the stop S to position same in the collar C, the legs 51a are held in a retracted position with a surrounding sleeve (not shown) in the well known manner. Such sleeve is removed by a wire line or other known means to allow the legs 51a to expand into the recess C, as shown. One or more ports or openings 51C are provided to allow fluid to pass therethrough so as to establish fluid communication between the areas above and below the stop means S.

In the operation of the present invention, the stop S or any other suitable stop is positioned in the pipe T in the usual manner above the producing horizon from which the iluid and/or gas is being taken. Thereafter the plunger P is inserted into the pipe T with the laterally extending wiper arms in the retracted position thereby allowing the plunger P to fall freely through the pipe T until the release pin or rod 50 contacts the surface 51 of the stop S. When the release pin or rod 50 strikes the stop S, the r-od 50 is urged upwardly in the bore 10j and compresses the spring 45 to move the locking head 41 upwardly above the locking pins 40 so as to permit movement of the pins 40 inwardly into the bore 101C. Thereafter, the spring 22 moves the entire mandrel 10 downwardly relative to the body 20 as the locking pins 40 are moved inwardly by reason of their engagement with the lower inclined usrface of the groove 20h.

The downward movement of the mandrel 10 by the spring 22 imparts downward movement to the expander sleeve 14 by the co-action between the shoulders 11C and 14b. As the mandrel 10 and the expander sleeve 14 move downwardly together in relation to the body and to the wiper members 30, the inclined surfaces 30b and 30C of the wiper arms 30 are engaged by the similarly inclined surfaces 14e and 14j of the expander sleeve which urges the wiper elements 30 outwardly into engagement with the pipe T. As the segmental members 30 expand laterally, the interlocking iingers 30e and 30j" form a seal about the entire circumferential pipe T closing off the annular `space between the plunger P and the pipe T.

The fluids and gases rising inthe pipe T pass through the ports 51e of the stop S and exert an upward lifting force on the expanded plunger P causing it to rise in the pipe T. Wiper members 30 in engagement with the pipe T wipe or scrape paraiiin or other foreign material from the inner surface olf the pipe T and carry such material upwardly to the exhaust port T as illustrated in FIG. 1 of the drawings. i Y

As the plunger P is raised in pipe T as illustrated in FIGS. l and 2 of the drawings, the actuating assembly A which is positioned in the pipe T at the upper limit of the travel off the plunger is locked in the expanded position with the actuator body 62 locked by the locking pin or pins 61 in relation to the actuator base 60.

When the plunger P contacts the actuating assembly A, the inclined annular surface 14C of the expander sleeve 14 engages the similarly inclined annular surface 62d of the actuator sleeve 62. The expander sleeve 14, the body 20, and the wiper arms 30 of the plunger P are thus temporarily held .against further upward movement While the pressure of the fluids and gases in the well continues to force the mandrel 10 and the nut 11 upwardly, moving the upper surface 11b of the nut 11 above the upper end 14C and into engagement with the lower surface 64d of the release lpiston 64. Thus, the sleeve 62, when in latched position, serves as stop means for engagement with expander means 14 to temporarily stop such expander means while the opening 62d permits upward movement `of the mandrel 10.

Such upward movement of the mandrel 10 continues after the engagement of the nut 11 with the piston 64 to urge the piston 64 upwardly in the actuator sleeve 62, and at the same time, to move the locking pins 40 into lateral alignment with the annual groove 20h. When the pins 40 are thus aligned, the spring 45 urges the locking head 41 downwardly, the tapered surface 41b forcing the locking pins 40 outwardly into the annular groove 20h. Then the spring 45 moves the portion 41a into position adjacent the pins 4() to lock them in the expanded position in the annular groove 20h and thereby to lock the mandrel 10 to the body 20.

Substantially simultaneously with, or shortly after, the locking of the pins 40 in the groove 20h, the nut 11 moves the piston 64, release rod 63e and the locking head 63 upwardly to .position the head 63 sufficiently above the pins 61 to allow such pins 61 to move inwardly to a retracted position (FIG. 4). In order to -provide some time delay between the locking of the pins 40 in the groove 20h and the release of the pins 61 from the groove 62k, it is preferable to make the groove 20h with greater longitudinal or vertical extent than the diameter of the pins 40 so that there is sorne s-mall amount of travel of the mandrel 10 upwardly relative to sleeve 14 alfter the pins 40 are expanded into the groove 20h. Such additional travel assures the locking of the mandrel 10 and body 20 together before the sleeve 62 is released for upward movement relative to the base 60.

The upward movement of the mandrel 10 relative to the body 20 is stopped by either the engagement of shoulders 10c and 20e or by the engagement of the upper surfaces of the pins 40 with upper inner surfaces of the groove 20h. During the upward movement of the mandrel 10 relative to the body 20, the springs 22 and 25 are both compressed (FIG. 3).

A-fter the locking pin or pins 61 have been withdrawn from the actuator grooves 62b, the actuator sleeve 62 is then free to move upwardly over the actuator base 60. With the sleeve 62 free to move upwardly relative to the base or body 60, the spring 2S together with iluid pressure below the plunger P act to cause the sleeve 62 -to move to an upper lposition (FIG. 4) and to also further move the piston 64 upwardly to further compress the springs 63d and 65 (FIG. 4). It is to be noted that the spring 25 moves the expander sleeve 14 upwardly relative to the mandrel 10 .after the release of the sleeve 62 permits such relative movement, thereby allowing the wiper members 30 to retract inwardly from their expanded position. The inward retraction of the members 30 is facilitated by a co-action onf the lower edge of the hook 25C off each link 25 with the inclined surface 17h which causes the lower end of each link 25 to be pivoted outwardly as the sleeve extension moves upwardly relative thereto. Such outward pivoting of the lower ends of the links 25 results in a corresponding inward pivoting of the portions of the links 25 above the pivot pins 32 so as to swing the members 30 inwardly to the retracted position (FIG. 4).

With the members 30 thus retracted, the plunger P may fall freely by gravity due to the annular external 'Dy-pass of fluid around the plunger. Because of the relatively large area of the annular external by-pass, the plunger P falls without impedance of any consequence, and therefore falls very rapidly. Also, since the actuating assembly A is in an activated condition by the compressi-on of the spring 65 at the end of the upward movement of the plunger P, such assembly A serves to give the plunger P an additional downward kick or force to further increase the speed at which the plunger returns to its lower point in the pipe T. If such actuating assembly A were not used, but instead merely an annular shoulder corresponding to the lower end of the sleeve 62 were used, the extra kick or force would not be provided for returning the plunger P, but the force of gravity would be sufticent to cause its return, particularly in view olf the large external annular by-pass provided.

It is to be noted that the members 30 are held in a locked retracted position during the fall of the plunger P due to the locking of the pins 40 in the annular groove 20h which locks the body 20 to the mandrel 10. Therefore, any inadvertent return of the members 30 to an expanded position during the free ffall of the plunger P is avoided.

When the plunger P reaches its lower position at the stop S, the release pin S contacts the upper surface 51 to move the pin 50 upwardly and thus release the locking pins 40 so that the members 30 are again expanded, as previously explained. The plunger P then is forced upwardly in the pipe T for the next stroke for lifting the oil and/or ygas and for scraping paratlin or other deposits from the pipe T during the stroke.

Although the plunger P is intended to operate with the release pin 50 at the lower end as shown, the plunger P may be reversed and run upsidedown with the release pin 50 at the top under some circumstances. In that case, the plunger P could be forced downwardly by pressure from above and then lifted by a suitable wire line or retrieving means. Also, under some circumstances the plunger P may be operated horizontally or in other non-vertical directions.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within t-he scope of the appended claims without departing from the spirit off the invention.

What is claimed is:

1. A plunger for use in a well pipe, comprising:

(a) a body adapted to extend longitudinally in the well pipe,

(b) expansible means mounted on said body for movement outwardly into engagement with the inner surface of the well pipe,

(c) expander means for expanding said expansible means outwardly so that flruid pressure therebelow may move the plunger upwardly in the well pipe, and

(d) said expansible means including (l) a plurality of segmental wiper elements each of which is movable outwardly by said expander means,

(2) interconnecting means on said elements for providing a continuous annular seal with the inside surface of the well pipe, and

(e) means with said expander means for moving said wiper elements inwardly.

2. A device for use in a pipe having a stop means disposed therein, comprising:

(a) a body adapted to extend longitudinally in a pipe,

(b) expansible means mounted on said body for movement outwardly into engagement with the inner surface of the pipe whereby fluid pressure in the pipe will act thereon in a longitudinal direction,

(c) expander means on said body for expanding said expansible means outwardly so that tiuid pressure acting on the expansible means may move the device longitudinally,

(d) latch means engageable with said body for releasably holding said expander means in a retracted position,

(e) release means operably connected to said latch means and operable by engagement with the stop means in the pipe for releasing said latch means, and

(f) means engageable with said expander means and said body for moving said expander means longitudinally relative to said expansible means to urge said expansible means outwardly into engagement with the pipe.

3. A device for use in a pipe having a stop means disposed therein, comprising:

(a) a body adapted to extend longitudinally in a pipe,

(b) expansible means mounted on said body for movement outwardly into engagement with the inner surface of the pipe,

(c) a mandrel extending longitudinally of said body,

(d) expander means on said mandrel for expanding said expansible means outwardly so that fluid pres- 10 sure `acting on the expansible means may move the device longitudinally,

(e) latch means engageable with said Ibody Ifor latching said mandrel and said body together,

(f) said mandrel being movable longitudinally upwardly relative to said body for positioning said latch means latching position to latch said body and mandrel together, and

(g) means for moving the expander means longitudinally upwardly with respect to said mandrel after said body and said mandrel are latched together t0 permit retraction of said expansible means.

4. A plunger for use in a well pipe, comprising:

(a) an inner mandrel,

(b) an expander sleeve slidably disposed on the upper portion of said mandrel,

(c) a tubular body surrounding said mandrel at its lower position,

(d) expansible means disposed around said expander sleeve,

(e) means pivotally connecting said expansible means to said body,

(if) a latch pin mounted on said mandrel `for lateral movement,

(g) a latch recess in said body for receiving the latch pin when the pin in its extended position to hold said expander sleeve in a retracted position relative to said expansible means,

(h) a release rod slidably disposed in the mandrel and having a locking head for holding the latch pin in said extended position,

(i) said release rod being movable relative to the mandrel for moving the locking head longitudinally away from said latch .pin to thereby effect a release of the mandrel from the body, and

(j) means for moving the mandrel and the expander sleeve therewith to a position for expanding the expansible means.

5. An apparatus rfor use in a well pipe, comprising:

(a) a plunger having:

(l) a mandrel,

(2) wiper means expansible into engagement with the inside of the well pipe and retractable therefrom,

(3) expander means on said mandrel and engageable with said wiper means for expanding said wiper means out wardly into engagement with the inner surface of the well pipe, and

(4) latch means operably connected to said expander means for releasably holding the expander means in a retracted position and being movable from a release position to a latched position upon upward longitudinal movement of the mandrel relative to the expander means, and

(b) an actuating 4assembly in the well pipe at the upper limit of travel of said plunger for co-operating with said plunger for effecting a retraction of the wiper means, having:

(1) stop means engageable with said expander means for temporarily stopping said expander means on its upstroke while permitting upward movement of the mandrel to effect a latching of said latch means, and

(2) release means lfor thereafter releasing said stop means for allowing the expander to move upwardly relative to the mandrel to its retracted postion.

References Cited bythe Examiner UNITED STATES PATENTS (Other references on following page) UNITED 1 l l 2 STATES PATENTS 2,850,339 9/1958 Vincent 103--52 f 2,865,455 12/1958 Rhoads 166-170 Pestman et EL 166-7170 2,893,493 7/1959 copas 16e- 170 FUIZ 166--237 Taylor 166-170 5 CHARLES E. OCONNELL, Primary Examiner. Curnlltt et al. 166-170 C. D. JOHNSON, I. A. LEPPINK, Assistant Examiners. 

2. A DEVICE FOR USE IN A PIPE HAVING A STOP MEANS DISPOSED THEREIN, COMPRISING: (A) A BODY ADAPTED TO EXTEND LONGITUDINALLY IN A PIPE, (B) EXPANSIBLE MEANS MOUNTED ON SAID BODY FOR MOVEMENT OUTWARDLY INTO ENGAGEMENT WITH THE INNER SURFACE OF THE PIPE WHEREBY FLUID PRESSURE IN THE PIPE WILL ACT THEREON IN A LONGITUDINAL DIRECTION, (C) EXPANDER MEANS ON SAID BODY FOR EXPANDING SAID EXPANSIBLE MEANS OUTWARDLY SO THAT FLUID PRESSURE ACTING ON THE EXPANSIBLE MEANS MAY MOVE THE DEVICE LONGITUDINALLY, (D) LATCH MEANS ENGAGEABLE WITH SAID BODY FOR RELEASABLY HOLDING SAID EXPANDER MEANS IN A RETRACTED POSITION, (E) RELEASE MEANS OPERABLY CONNECTED TO SAID LATCH MEANS AND OPERABLE BY ENGAGEMENT WITH THE STOP MEANS IN THE PIPE FOR RELEASING SAID LATCH MEANS, AND (F) MEANS ENGAGEABLE WITH SAID EXPANDER MEANS AND SAID BODY FOR MOVING SAID EXPANDER MEANS LONGITUNDINALLY RELATIVE TO SAID EXPANDER MEANS TO URGE SAID EXPANSIBLE MEANS OUTWARDLY INTO ENGAGEMENT WITH THE PIPE. 